Cooling system for internal combustion engines



C. R. BUTLER May 12, 1964 COOLING SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed Sept. 10, 1962 /6` Z5 W R E Y o a E 3 ma M mf 7 Mp. a L 7 f W e f w o WM 4 T 9 e o 74M 6 y m hm.. 2 Y .n. 1.4 20u AA f z m W M.

3,132,634 CUOLING SYSTEM FOR INTERNAL COMBUSTION ENGINES Charles R. Butler, RR. 3, Bax 158, Pendleton, Ind. Filed Sept. 10, 1962, Ser. No. 222,457 7 Claims. (Cl. 123-41.54)

This invention relates to internal-combustion engine cooling systems and in that respect resembles, and is an improvement upon, the invention set forth and described in my prior Patent 2,799,260 granted luly 16, 1957.

The vconventional pressurized engine-cooling system used in present-day automobiles embodies, at the top of the radiator, a pressure-relief valve that prevents the escape of fluid from the cooling system until the pressure therein has attained a value at which the valve opens. Accordingly, as the engine warms up after being placed in operation, the resultant expansion of the liquid coolant increases the pressure in the system to the maximum determined by the pressure at which the relief valve is designed to open. If any fluid escapes past the relief valve during engine operation, it is usually deemed necessary to replace it after the engine has stopped and cools', in order to prevent the creation of an undesirable vacuum in the cooling system. This is taken care of in the conventional system by providing an inwardly opening check valve through which air may enter the system as the coolant cools and contracts. At least during the initial stages of engine operation, therefore, there is a pocket of gaseous matter trapped in the system. As the liquid coolant warms up and expands with continuing engine operation, such trapped gaseous matter acts as a cushion absorbing the thermal expansion of the coolant and retarding the build-up of system-pressure to the desired value.

My aforesaid prior patent provided means for replacing with coolant, rather than with air, any fluid which escaped past the pressure relief valve during operation and in that way promoted maintenance of the cooling system in a condition free from gaseous matter pockets. However, the elimination of gaseous matter, and of its effect, from the system was a relatively slow process. If a relatively large amount of gaseous matter ever became entrapped in the system, several periods of engine operation, with intervening periods of cooling, might be required before all of it was eliminated. That delay deferred attainment of the operating pressure and the benefits which would flow therefrom.

It is the object of the present invention, not only to promote the elimination of gaseous matter from an internal-combustion engine cooling system, but also to attain substantial elimination of gaseous matter or its effect more quickly than was done in the system of my prior patent. A further object of the invention is to accompany the elimination of gaseous matter with maintenance of an increased operating temperature.

In carrying out the invention, I provide an auxiliary coolant tank that is open to atmosphere and connected through a check-valve to the inlet of the cooling-system pump, and I also provide for delivery to the auxiliary tank of any liquid coolant which may escape past the pressurerelief valve, all as in my prior patent. In addition, the present invention employs, between the top of the radiator and the pump-inlet, a connection through which fluid, gaseous or liquid, at the top of the radiator is drawn into the pump inlet and discharged into the coolant jacket of the engine. To facilitate incorporation of the invention in systems not already provided with a pressure-relief valve, I may embody a pressure-relief valve in a unitary valve structure with the aforesaid check valve, such valve structure being one which can be readily mounted in close association with the engine and radiator.

Further objects and features of the invention will be- United States Patent O Patented May 12, 1964 ICC c ome apparent from the following more detailed description and from the accompanying drawing, in which:

FIG. 1 is a somewhat diagrammatic view of an automobile-engine cooling system of the type which already embodies a pressure-relief valve, my unitary valve structure being shown on an enlarged scale relative to other elements of the system;

FIG. 2 is a fragmental view illustrating a pressure-relief valve of the type commonly mounted in the filler neck of a cooling-system radiator; and

FIG. 3 is a view similar to FIG. 1 showing a system in which the only pressure-relief valve is that embodied in the unitary valve structure.

The system shown in FIG. 1 comprises a jacketed engine 10, a coolant pump 11, and a radiator 12 the bottom of which is connected to the inlet tting 13 of the pump 11 and the top of which receives coolant from the engine 10 through a connection 14. The radiator has the usual ller neck 15 closed by a removable cap 16.

It is contemplated that in the system of FIG. 1 a pressure-relief valve, which may be of conventional type, will be provided in the filler-neck 15. Such a valve is shown in some detail in FIG. 2. As there illustrated, the valve comprises a seat 18 and a cooperating valve member 19 urged downwardly against the seat by a compression spring 20. The force exerted by that spring on the valve member 19 determines the maximum pressure that can exist in the system, and when system-pressure builds up to that at which the valve 19 opens, fluid escapes from the radiator past the valve and into the filler neck 15, from which it is carried away via a tube 21.

The unitary valve structure above referred to is shown in FIGS. 1 and 3 on a greatly enlarged scale relative to the other elements of the system. It comprises a body 22, conveniently of metal, provided with two parallel through passages 23 and 24 screw-threaded at their ends for the reception of fittings (not shown) through which they are connected to the various conduits to be described below. The two through passages are interconnected by two cross passages 25 and 26, the former containing a check-valve 27 opening toward the passage 23 and the latter containing a pressure-relief valve 28 opening toward the through passage 24 and urged toward its seat by a compression spring 29. The spring 29 reacts against a screw 30 which is mounted in the body 22 and can be adjusted to vary the iluid pressure at which the valve 28 opens. Near its center, the body 22 is shown as provided with a through hole 31 for `the reception of a mounting screw.

When the valve structure just described is used, as in FIG. l, in a system already possessing a pressure-relief valve, one end of the passage 23 is connected through a conduit 33 with the inlet 13 of the coolant pump 11, while its other end is connected to a conduit 34 communicating with the top of the radiator, as indicated at 35. One end of the passage 24 is connected by a conduit 36 to the lower portion of an auxiliary, vented coolant tank 37, while the other end communicates by way of a conduit 38 with the tube 21 through which fluid passing the conventional pressure relief valve of FIG. 2 escapes from the ller neck 15.

When the engine of FIG. l is placed in operation, the pump 11 draws coolant from the bottom of the radiator and discharges it under pressure into the coolant jacket of the engine. Through the conduits 33 and 34 and passage 23, the pump also draws fluid from the top of the radiator and discharges it into the coolant jacket. Whether the iluid initially drawn from the top of the radiator is liquid or gaseous depends upon whether the initial coolant level in the radiator is above or below the point 35 at which the conduit 34 communicates with the radiator; but in the latter case withdrawal of the gaseous uid will almost immediately cause the coolant level to rise to the point 35, thus reducing the volume of the trapped gas to the space between the point 35 and the valve seat 13. I find that this rapid reduction in the volume of gaseous iluid trapped at the top of the radiator promotes a rapid rise in system pressure as the coolant warms up and cxpands. I am not sure why this should be so. Any gas withdrawn from the radiator enters the pump 11 and becomes subject to the discharge pressure of the pump, thus promoting its dissolution in the coolant and thereby reducing the volume of free gaseous lluid in the system. Also, gaseous matter entering the pump inlet becomes dispersed in the coolant as a multiplicity of line bubbles, and that change in the form of the gaseous matter may lessen its ability to act as a cushion reducing the pressure increase caused by thermal expansion of the coolant.

In the system of FIGS. 1 and 2, the two pressure-relief valves 19 and 28 are, in effect, arranged in parallel with the result that maximum system pressure is determined by the valve which opens at the lower pressure. Whichever valve opens to relieve pressure, the iluid passed by the valve flows into valve passage 24 and therefrom into the auxiliary tank 37. When, after the engine ceases to operate and the coolant contracts to reduce system-pressure, any lluid which escaped during engine operation is replaced by coolant drawn from the tank 37 past the check valve 27.

The system of FIG. 3 is similar to that of FIG. 1 except that the outlet 21 and the pressure-relief valve of FIG. 2 are omitted from the ller neck with the result that the only egress for iluid at the top of the radiator is by way of the conduit 34. Since there is no outlet 21, the conduit 38 is eliminated and the one end of the valve passage 24 is closed with a plug 40. The operation of the system shown in FIG. 3 is the same as that of FIG. l except for the fact that the pressure-relief valve 28 alone determines maximum system pressure.

In both systems shown, the conduits 33 and 34 and valve passage 23 constitute a by-pass around the radiator 12. Coolant owing through such by-pass returns to the engine at a higher temperature than it would have if it passed through the radiator, thereby tending to cause an increase in the normal operating temperature of the engine. The extentof that tendency depends upon the length and minimum cross-sectional area of the by-pass and the nature and location of its connection into the cooling system, and can be Varied as desired. For the engines of the larger present-day passenger automobiles I find that a by-pass 1A to 1% of an inch in diameter will not result in an undue increase in engine temperature. In fact, I believe that raising the normal operating temperature of the engine is benecial in inhibiting the accumulation of carbon deposits in the cylinders and in promoting complete fuel combustion. Because of the effect of my invention in promoting the maintenance of high cooling system pressure, engine temperatures higher than those ordinarly employed can be used-without unduly increasing the possibility of undesirable coolant- Vaporization.

I claim as my invention:

1. In combination with the cooling system of a jacketed internal combustion engine, said system including a radiator, a coolant pump forwithdrawing coolant from the bottom of the radiator and delivering it to the engine jacket, and a pressure-relief valve controlling communication between the cooling system and the atmosphere; an auxiliary coolant tank for containing a supply of coolant in addition to that circulating in the cooling system, a connection between said auxiliary tank and the pump inlet, a check valve in said connection permitting llow from the auxiliary tank to the pump but preventing flow in the reverse direction, and a connection between the top of the radiator and the pump inlet for applying pump-suction to fluid at the top of the radiator.

2. The combination of claim l with the addition that said pressure-relief valve is located at the top of the radiator above the point at which said last named connection communicates therewith.

3, The combination of claim 2 with the addition of means for conducting to said auxiliary tank any liquid which escapes from the cooling system past said pressurerelief valve.

4. In combination with the cooling system of a jacketed internal combustion engine, said system including a radiator, a coolant pump for withdrawing coolant from the bottom of the radiator and delivering it to the engine jacket, and a pressure-relief valve controlling communication between the cooling system and the atmosphere; an auxiliary coolant tank, means operative upon the occurrence of subatmospheric pressure in the cooling system for replacing with coolant from said auxiliary tank, any uid expelled from the system past said pressurerelief valve, and a connection between the top of the radiator and the pump inlet for applying pump-suction to tluid at the top of the radiator.

5. In combination with the cooling system of a jacketed internal combustion engine, said system including a radiator, a coolant pump for withdrawing coolant from the bottom of the radiator and delivering it to the engine jacket, an auxiliary coolant tank for containing a supply of coolant in addition to that circulating in the system, a valve body having first and second ports and first and second passages interconnecting said ports, conduits connecting said rst port respectively with the top of the radiator and the inlet of said pump, a conduit connecting said second port with said auxiliary tank, a pressurerelief valve in said rst passage opening toward the second port, and a check valve in said second passage opening toward said first port.

6. The combination of claim 5 with the addition of means mounted in said body for adjusting said pressurerelief valve.

7. The combination of claim 5 with the addition of a second pressure-relief valve at the top of said radiator, and a conduit for delivering to said second port liquid expelled from the radiator past the second pressure-relief valve.

References Cited in the le of this patent UNITED STATES PATENTS 2,799,260 Butler July 16, 1957 

1. IN COMBINATION WITH THE COOLING SYSTEM OF A JACKETED INTERNAL COMBUSTION ENGINE, SAID SYSTEM INCLUDING A RADIATOR, A COOLANT PUMP FOR WITHDRAWING COOLANT FROM THE BOTTOM OF THE RADIATOR AND DELIVERING IT TO THE ENGINE JACKET, AND A PRESSURE-RELIEF VALVE CONTROLLING COMMUNICATION BETWEEN THE COOLING SYSTEM AND THE ATMOSPHERE; AN AUXILIARY COOLANT TANK FOR CONTAINING A SUPPLY OF COOLANT IN ADDITION TO THAT CIRCULATING IN THE COOLING SYSTEM, A CONNECTION BETWEEN SAID AUXILIARY TANK AND THE PUMP INLET, A CHECK VALVE IN SAID CONNECTION PERMITTING FLOW FROM THE AUXILIARY TANK TO THE PUMP BUT PREVENTNG FLOW IN THE REVERSE DIRECTIN, AND A CONNECTION BETWEEN THE TOP OF THE RADIATOR AND THE PUMP INLET FOR APPLYING PUMP-SECTION TO FLUID AT THE TOP OF THE RADIATOR. 